Jesus went to Capernaum on the Sea of Galilee.
It was a very prosperous city. There were a
lot of people brought to Him for healing while
He was there.

"And they went into Capernaum; and straight
way on the sabbath day he entered into the
synagogue, and taught. And they were
astonished at his doctrine: for he taught them
as one that had authority, and not as the scribes.
And there was in their synagogue a man with an
unclean spirit; and he cried out, Saying, Let us
alone; what have we to do with thee, thou Jesus
of Nazareth? art thou come to destroy us?
I know thee who thou art, the Holy One of God.
And Jesus rebuked him, saying, Hold thy peace,
and come out of him. And when the unclean
spirit had torn him, and cried with a loud voice,
he came out of him. And they were all amazed,
insomuch that they questioned among them
selves, saying,What thing is this? what new
doctrine is this? for with authority commandeth
he even the unclean spirits, and they do obey
him. And immediately his fame spread abroad
throughout all the region round about Galilee."
Mark 1:21-28

He not only spoke with authority but He also
had authority over evil spirits. The powers He
had before He came to earth were showing in
His ministry by now.